Applied online. Was setup an appointment for a technical phone interview. That was a 30 minute call. That was followed by an impromptu call 10 days later for a 45 minute technical interview with another manager. Two weeks later, another technical interview was scheduled with a manager at a different office. Not sure what they were trying to gauge. Finally, was scheduled for an on-site interview 2 weeks later. So I flew in to the office, attended the 3-4 hour interview, with the same 2 managers who interviewed me before. In addition, interviewed with the director, who asked behavioral questions.
All along these phone and face-to-face interviews they had long discussion about the various projects and the thesis that I described on my resume. So at the end of the long interview process, felt confident they would hire me.